Spray with round-up or equivalent. And treat with Preen as if it were a landscape bed, otherwise, all the weeds will be right back.

You've discovered why landscape fabric is a poor choice. It doesn't stop weeds and it makes their removal difficult because you can't dig. You could break out the hoe on a dry day. If you have the time and energy I'd remove the fabric.

Yes, remove the fabric before removal gets even more problematic. It's awful stuff--worthless too.

I have a similar issue on the edge of my flower beds... the crabgrass keeps creeping up. Is there a particular round up that’s best? And how long after do you apply the Preen? Thank you!

Short term, Yardvaark has the right answer. Long term, mulch is not a good option for a permanent groundcover, as you've seen. Whether it's grass or some sort of groundcover plant, you need something more than just mulch unless you REALLY like pulling weeds.

Mulch works very well to control weeds....IF you give it the attention it needs!! Two years is a long time to go in between mulching. It needs to be refreshed anually and raked periodically to loosen and remove any annual weeds that can blow in. It is not exactly a 'lay a mulch and then forget about it' situation!! Like anything to do with gardening, it will require periodic maintenance to look good and function properly.

And count me in the camp for getting rid of any landscape fabric. It simply does not work well and usually causes more problems than it solves.

Weed, freshen mulch, apply Preen or corn gluten. Ask me how I know. Get those thistles out of there before they go to seed. Ask me how I know . . .

Mulch is a fantastic long term ground cover that suppresses weeds. You just need to use it properly which means maintaining 6” of mulch. Most people only put 2" which is actually beneficial to weeds. You can't really blame the much when it is used improperly.

I don't disagree that a thick mulch can suppress weeds, I just don't understand why anyone would opt for a vast ocean of mulch long term when there are much more attractive and lower maintenance options.

Because it's not the ecological disaster that grass is in California?

Thanks for all the suggestions! We went for the mulch to replace dead grass because Brown was the new Green in CA few years back :)

@Nil13 I don't see anywhere in the OP's post where they said they were in CA, so since there are 49 other states that's not where I immediately went. Besides, I would think from an ecological standpoint that properly chosen, xeriscape or low intensive plantings are better than vast swaths of open mulch.

Agree with everyone, rip up the fabric, a 2for1 deal, get the weeds out at the same time. Mulch only lasts a couple of years before it needs refreshing. Aren’t there any native or drought tolerant ground covers or plants you could use with the mulch?

The question was also posted in California Gardening so the assumption is that's where they're located. I've missed that info. myself in the past and wondered how people seemed to know where the poster lived.

The OP is in California Gardening. Pretty safe to assume they are in CA where we don't get rain for at least six months straight.

Please please please DO NOT use Roundup. The tragedy of this pesticide just begins to be revealed recently and so much more is to come. Do not inflict this chemical on any area where humans, animals or water/runoff will be in possible contact.

https://www.pbs.org/newshour/health/what-you-need-to-know-about-a-popular-weed-killers-alleged-link-to-cancer

Lowe's is selling bags of mulch from Scott that contain Preen. What a great concept. I use groundcovers wherever I can, but for some areas where I still need mulch, I have started buying this. Haven't used it long enough to know how well it works.

Agree with DCF440, please do not use round up. The main ingredient in round up (Glyphosate) has been found in our food and water and has been linked to cause cancer. If this were my yard, I would remove the landscaping fabric and try sheet mulching instead. This involves placing cardboard over the area and putting mulch on top. This takes away the light source and will kill the weeds over time. You can get large cardboard boxes at bike shops or perhaps Costco.

Keep in mind, weeds will always settle in your yard, as they will blow in from nearby yards. Weeds can grow anywhere, which is why they are referred to as weeds. Using round up may get rid of the problem up front, but in the long term they always come back and you just have to manage them early on and get rid of them before they go to seed.

Thanks for all the suggestions. Lots of good info here! Short term - I am going to try my best to remove the weeds & re-mulch.

I don't use round up. I usually use 30% strength vinegar mixed with soap & water and that has worked well for me when applied under sun. May be more work than round up but its ok.

The weeds are on the soil on top of the fabric blown by window so sheet mulching will have same issue. With the on/off rains in California this year, I couldn't control the weeds in time.

Does anyone have suggestions for a walkable ground cover/alternative to grass suited for N.California that I can use to replace the mulch/fabric?

Is this around a raised/irrigated plant bed area? If so, and if it's a fire area, you might consider gravel. I have this set up. Highly walkable but not in bare feet. There is pea gravel but that tends to roam and be messy.

Roundup only kills weeds if you spray on tender new growth. After that, it takes a stronger solution and way more work that it is worth. Weed and then apply Preen. Way easier, since it keeps new weeds from even sprouting. Still won't mean you won't have to do a spot weed of the area every week though.

I took a class on CA native grasses and our instructor (Carol Bornstein) talked about a few that could be used as lawn alternatives.

Agrostis pallens, creeping bentgrass

Bouteloua gracilis, blue grama - she specifically mentioned "Blonde Ambition" and said once established it needs very little water and can be mowed.

Carex pansa, dune sedge - pretty tough and can be mowed

Carex praegracilis, clustered field sedge - only fault is it can be prone to rust.

Why don't you back up and show the whole area? Maybe someone can advise groundcover.

I hoe when I get occasional weeds in mulched area. They come up easily. That is why I don't like landscape fabric under mulch.

Use several layers of old newspaper in place of black plastic weed barrier if you want a more environmentally friendly way to reduce weed growth through your mulch.

https://centenarylandscaping.com.au/

Or cardboard.

Spread a layer of black plastic weed barrier over the planting area. Then apply organic mulch layer of 3-4 inch on it. Don't let show the black plastic. For that spread mulch over it. Either way, seek help from professional lawn care services for weed removal.

Please, no plastic. And why would you need professional lawn care experts if you're mulching, not trying to grow a lawn? Weeds respond to basic techniques like hoeing, pulling or, if you must, herbicides, etc. You don't need to pay experts for that.

The thing maybe to realize is that you may have to go through a few years of weeding even with a good mulch regularly refreshed to get rid of all the weed seeds sitting in the soil. Some weed seeds will lay dormant for years.

Also, you have to pull the weeds BEFORE the weeds go to seed, so you are not replenishing your next spring's weed supply every year! After a few years there will be many less, some years hardly any, making it very manageable. After that, just remember to pull what weeds the birds and breezes bring in, BEFORE they go to seed.

Hoov, right on! Yes pull weeds before they seed and reduces work the next year. Sometimes life gets crazy and these things get away from us, but I make weeding them when they are tiny a priority so less work as the years go by. We have drought tolerant St. Augustine grass in front, which only needs water from April Fools until Halloween in SoCal. During our drought last year this established lawn was OK on the city limit of 10 minutes twice a week. It looked a little dry but survived fine until restrictions were over and we could increase the water a little. With no restrictions we water 36 minutes a week once per week just after sunset as follows: 12min water, 18 min rest, 12 min water, 18 min rest, 12 min water. This allows the water to soak deeply and develops a deep root system that can handle a little water restriction later if needed. Grass is just as easy to take care of as our low water landscaping in back that includes kangaroo paw, rock rose, creeping thyme and salvias. The back plants actually use similar water per square foot as the grass in front, but our grass is partly shaded and back is full sun. St. Augustine in full all day sun would need more water I think. We stop all water for the winter and it stops growing and goes dormant getting a nice golden brown that reminds us of winter grass in cold climates. As soon as April hits and we start watering it grows green fast. We also don’t mow in the winter, which is a nice break.

Please don’t use roundup! There is a reason France, Greece, Germany, Italy, have banned non-essential cosmetic pesticides, including glyphosate. You can use 5 or 20% vinegar and plain table salt as a spray if you’d rather do that then pull the weeds.

Thank you for all the insights and suggestions!!

Regarding roundup - I don't use Roundup. I use 20% vinegar + soap mix and that has worked well for me

Regarding current weeds - There is a landscape fabric intact under the mulch. The weeds are growing on top of it in the mulch layer. So cardboard/newspaper would have resulted in same situation. These are very flat weeds so hard to pull. A mistake is to not refresh the mulch after 2 years.

Some of you asked me to share a pic of the area so I have attached an image. Thanks again for all the help :)

A sharp Dutch hoe is the tool for flat weeds.

The thing about cardboard or paper is that it biodegrades. Landscape fabric doesn't. Over the years weeds root through it and they become impossible to remove. When the time ones, as it will, that you or the next occupier wants to remove the fabric it will be a terribly difficult job. Also you say you mulched two years ago and weeds have grown since. Really it's necessary to mulch more frequently and to keep on top of the weeds with regular attention. It's just not possible to have no weeds without regular maintenance.